Reversing ribbon advancing mechanism



y Sept 5, 1967 M. D. Tl-:lcHN'r-:R 3,339,697

REVERSING RIBBON ADVANCING MECHANISM Filed March 19, 1965 2 sheets-sheet 1 l I lnilmmllm UNIL I NVENTOR.

Spt. 5v, 1967 M. D. TEicHNER l 3,339,697

REVERSING RIBBON AVANCING MECHANISM filed March 19, 1965 I 2 Sheets-Sheet 2 Z, /9 /5 /5 y 2, j .2 Ff 43 4Z j f7 28 Mlhh 22 29 22a 22 f 5 f3 v Z5 l 29 i5 /Z INVENTOR. Mau/"ice l? Telle/90er' om( KQ@ HTTOE/EYS United States Patent O 3,339,697 REVERSING RIBBON ADVANCING MECHANISM Maurice D. Teichner, New Canaan, Conn., assignor, by

mesne assignments, to Practical Automation, Inc., Shelton, Conn., a corporation of Connecticut Filed Mar. 19, 1965, Ser. No. 441,204 9 Claims. (Cl. 197-161) The present invention relates to a mechanism for incrementally moving a ribbon of the type carrying ink against which imprinting characters are struck to effect printing on paper and more particularly to such a mechanism in which the ribbon is alternately wound and unwound on a pair of spools.

In many machines, such as adding machines, ltypewriters and similar devices, -a line of information is formed on paper by imprinting characters striking an inked ribbon against paper toV form an ink impression of the characters onto the paper. After forming each impression, the ribbon is advanced to present to the imprinting characters a different length of the ribbon to assure that the portion of the ribbon being struck will have sufficient ink to form the impression. In order to enable a ribbon to be utilized for many impressions, the ribbon is advanced continually in one direction by it being unwound from a full spool and wound on an empty spool until the former becomes substantially empty and the latter becomes substantially full. Then the ribbon is caused to be advanced in the other direction from the full spool to the empty spool and so forth. Though such ribbon advancing mechanisms have heretofore been suggested, they have been somewhat complex utilizing many parts with resulting expense and increasing probability of mal-functioning in order to provide the above results.

It is accordingly an object of the present invention to provide a reversing ribbon drive mechanism which is extremely simple in design and reliable in use and quite inexpensive to manufacture.

Another object of the present invention is to -provide a ribbon advancing mechanism wherein there is only one member that causes both the advancing movement of the ribbon and the sensing of lwhen a spool has become suiciently full to require the ribbon to be moved in the other direction.

Another object of the present invention is to provide a ribbon advancing mechanism that achieves the above objects and which is made of parts that may be economically produced and quickly assembled.

In carrying out the present invention a feature resides in the provision of having two spools that are mounted in spaced apart relation with the ribbon being unwound from one spool and wound on the other and caused to traverse a path in which it may be struck by imprinting characters or hammers. Positioned between the spools in alignment with the periphery of the ribbon on the spools is. a driving member consisting of a wheel that is mounted for rotation and is actuated by a ratchet means to rotate the member incrementally after each impression. The member transmits its rotational movement to the spool on which the ribbon is being wound by having its periphery frictionally engage the periphery of the ribbon on said spool, the friction constituting the driving engagement therebetween. Thus by continually advancing the wheel in one direction by the ratchet mechanism the wheel causes the spool whose ribbon it engages to be rotated in the direction which causes the winding of the ribbon on the spool.

The wheel is also mounted to shift from the one spool on which ribbon is being -wound to the other spool whenever the one spool is substantially filled with ribbon. When engaging the other wheel, it also causes winding of the ribbon on the other spool as it is incrementally rotationally moved by frictional engagement between its periphery and the periphery of the ribbon -on the other spool. The wheel is mounted on a pivoted member which enables it to shift from one spool to the other and to effect shi-fting when the spool being driven is substantially full there is provided a camming mechanism having an over-center condition on one side of which the wheel is urged toward the one spool until the increasing diameter of the ribbon wound on the spool causes the mechanism to pass its over-center condition and shift the wheel to engage the ribbon of the other spool. The over-center mechanism not only effects shifting of the wheel from the one spool to the other spool but also provides a resilient force which urges the wheel against the ribbon on both positions of the wheel.

Other features and advantages will hereinafter appear.

In the drawing:

FIGURE 1 is a front view of the reversing ribbon advancing mechanism of the presentinvention.

FIG. 2 is a plan thereof.

FIG. 3 is a side view thereof.

FIG. 4 is a front view similar to FIG. l showing the position of the parts of the mechanism when the ribbon is being wound on the left-hand spool.

FIG. 5 is a View similar to FIG. 4 showing the position of the parts of the mechanism when the ribbon is being wound on the right-hand spool.

FIG. 6 is a section taken on the line 6-6 of FIG. 1 showing a detail of construction.

Referring to the drawing, the ribbon advancing mechanism is generally indicated by the reference numeral 10 and includes aframe 11 that has an outwardly extending plate 12. Secured on the plate 12 in spaced relation are a pair of shouldered rods 13 and 14 which support lefthand spool 15 and right-hand spool 16 respectively and as the two rods 13 and 14 are aligned and parallel, the axis of the two spools is thus aligned and Iparallel. Slotted thum-b nuts 17 and 18 are releasably threaded onto the ends of the rods 13 and 14 respectively to maintain the spools on the rods and yet permit substitution thereof, it being appreciated'that each end of the spools is freely rotatable on its shouldered rod. I

An elongate ink carrying ribbon 19 has its end Iportions secured to the core of spools 15 and 16 in any conventional manner and in the embodiment shown herein is guided along a path to present an exposed flat length 19'. Striking characters (not shown) may be positioned on one side of the length 19 and paper (not shown) on the other so that when the paper, ribbon and imprinting characters are brought together, a mark is made on the paper. Specically, the length 19' of the ribbon 19 is achieved by the ribbon 19 being guided around a somewhat rectangular chamber 20 by guiding devices 21. The particular chamber 20 and guides 21 are merely set forth to disclose one example sho-wing the path which the ribbon may traverse, it being appreciated that the present invention is not limited thereto but includes other and different guides and paths of the ribbon. The ribbon in its path of travel is caused to be wound on a substantially empty spool and then wound from a substantially full spool until the former becomes substantially full and the latter becomes substantially empty at which time thereversing procedure takes place with the ribbon advancing in the other direction. In the embodiment shown in FIG. 1, the right-hand spool 16 is almost substantially full of ribbon wound with its periphery being indicated by reference character 16'. The ribbon is being withdrawn from the spool by the spool 15 turning and the periphery of the ribbon is indicated by the reference character 15.

For rotating the spool 16 to cause the winding of the ribbon thereon and consequent unwinding of the ribbon from the spool 15, the latter being substantially free to rotate, there is provided a drive wheel 22 that includes a periphery 22 which is preferably formed to have a surface which has a substantial coecient of friction. The periphery 22', as shown in FIGS. 2 and 3, is of slightly less thickness than the distance between the anges of the spools and thus may pass between the flanges to engage the periphery 16' of the ribbon. The wheel 22 is secured to a shaft 22a that is rotatably mounted on one arm 23 of a crank 24 to enable rotation of the wheel with respect to the crank. A ratchet wheel 25 is also secured to the shaft 22a to rotate with the wheel 22. The ratchet wheel 25 cooperates with a pawl 26 that is spring urged against the ratchet wheel as by a spring 27 with the pawl being mounted for pivotal movement on a lever 28 pivoted as at 29 on the plate 12. A spring 29a urges the lever 28 counterclockwise. For actuating the lever 28 and consequently the pawl 26, there is provided an actuating link 30 pivotally carried by a U-shaped bracket 31 with the link including an end portion 32 that engages an end portion 33 of the lever 28, the spring 29a maintaining engagement therebetween.

It will accordingly be appreciated that if the link 30 is pivoted as indicated by the arrow 34 (FIG. 3) that for each such movement thereof the end portion 32 will pivot the end portion 33 of the lever 28 clockwise and as the latter carries the pawl 26, it will also move the pawl. The pawls movement, by its engagement with the ratchet wheel 25, is translated into an incremental counterclockwise rotational movement of the ratchet wheel and through the shaft 22a the same rotational movement of the drive wheel 22. The link 30 may be actuated in any convenient manner after there has been printing in order to present a different portion of the ribbon to the imprinting characters.

The crank 24 that carries the shaft 22a is pivoted as at 35 on the plate 12 and additionally has an arm 36 which extends at substantially right angles to the arm 23 and carries a one-way clutch member 37. The member 37 is pivotally mounted on the arm 36 and has an end 38 which engages the ratchet wheel 25 to prevent reverse rotation of the wheels 25 and 22. A spring 39 urges the one-way clutch member 37 against the ratchet wheel to maintain the engagement therebetween.

Pivoted on the plate 12 adjacent the spool 15 on a pin 40 is an elbow crank 41 having an arm portion 42 to which one end of a spring 43 is fastened, the other end of the spring 43 being secured to an abutment 44 carried by the plate 12. The crank 41 further includes another arm portion 45 that extends at substantially right angles to the arm portion 42 with the arm portion 45 being formed adjacent its end with a pair of substantially straight camming surfaces 46 and 47 that are angularly related to each other and intersect at an apex 48. Similarly the end portion of the arm 36 is formed with a pair of substantially straight camming surfaces 49 and 50 that are also angularly related to each other and intersect at an apex 51.

It will be understood that the spring 43 is under tension and urges counterclockwise movement of the elbow crank 41 to effect engagement between the camming surfaces 46 and 50 in FIG. 1. The rotational urging of the crank 41 causes the crank 24 to be urged clockwise to force the 4 periphery 22 of the drive wheel 22 against the periphery 16 of the ribbon on the spool 16.

In the operation of the mechanism, with the parts positioned as shown in FIG. 1, and the drive wheel urged against the periphery 16', actuation of the link 30 causes the spool 16 to be incrementally rotated to incrementally wind the ribbon about the spool 16 and unwind it from the spool 15. As the link 30 is continually actuated, the periphery of the ribbon on the spool 16 will increase in diameter until the spool is substantially full. Then the driving wheel is shifted to engage the periphery 15 of the spool 15 and cause it to be rotated to wind the ribbon thereon and unwind it from the spool 16. This latter condition is shown in FIG. 4 and results from the crank 24 being pivotally moved leftwardly to be urged against the periphery 15' of the ribbon. In this latter condition the camming surfaces 47 and 49 are in engagement and the elbow crank 41 urges the crank 24 counterclockwise to provide the compression between the drive wheel 22 and the periphery 15.

The change of the driving wheel 22 from that shown in FIG. 1 to that shown in FIG. 4 is effected when the periphery 16 of the ribbon on the spool extends just beyond the arc of a periphery denoted by the reference character 16". At this condition, the apex 51 of the arm 36 is substantially at the apex 48 of the arm portion 45. As the periphery 16' increases slightly more in diameter the crank 24 is forced leftwardly in FIG. l and the apex 51 passes beyond the apex 48. The crank 41 is pivoted counterclockwise by spring 43 and the camming surface 47 engages the camming surface 49. As the crank 24 is free to pivot, the crank 41 will continue pivoting which also causes pivoting of the crank 24 until the wheel 22 abuts the periphery 15 to prevent further movement. At this position, the engaging camming surfaces transmit the tension of the spring 43 to urge the drive wheel against the periphery 15.

With the periphery 15' increasing in diameter, the crank 24 is forced to pivot clockwise, forcing the crank 41 to pivot clockwise against the tension of the spring. Also the apexes 48 and 51 move closer together until the periphery 15 attains substantially the arc of the periphery 15 when the apex 51 will pass the apex 48 to cause the crank 42 to urge the drive wheel against the periphery 16 of the ribbon on the spool 16 by engagement between the camming surfaces 46 and 50.

It will be appreciated that in both positions of the drive wheel 22 that the pawl 26 drives the ratchet wheel and hence the wheel 22 in the same direction. The pivoting of the pawl accommodates for changes in position of the ratchet wheel with respect to the pawl while the spring 27 continually urges the pawl against the ratchet wheel. The continued clockwise rotation of the ratchet wheel causes the spool 15 to be rotated clockwise and thus wind the ribbon in this direction thereon, while the spool 16 is similarly driven in the same direction when the driving wheel engages the periphery 16 of the ribbon on the spool 16.

In order to prevent unwanted excessive unwinding of the ribbon from the spool there is provided for the spool 16, a spring pressed bar 52 pivoted as at 53 which is urged against the periphery of the ribbon to provide a slight resistance to movement thereof while a bar 54 pivoted as at 55 on the plate 12 is similarly spring urged against the periphery of the ribbon on the spool 15.

It has been found that the periphery of the drive wheel 22 may be advantageously made to have a suficient coeflicient of friction if the periphery consists of an abrasive material such as emery paper or sandpaper.

In addition to being extremely simple in design, the many parts of the present invention may be molded of plastic material to have the shapes shown, thus rendering further economies in the mechanism. Some of these elements include the ratchet wheel 25, shaft 22a, drive wheel 22 (except for its peripheral covering), link 28, cranks 24 and 41, member 37 etc.

It will accordingly be appreciated that there has been disclosed a reversing ribbon advancing mechanism which may advantageously be employed to provide the printing media for enabling characters to be formed on paper. The mechanism includes a pair of spools with the ribbon when advancing in one direction being wound on one spool and unwound on the other until the one spool becomes substantially full at which time the unfilled spool is rotated to cause filling thereof as the ribbon is unwound from the filled spool. For causing the unfilled spool to be rotated, the present invention utilizes a drive wheel which engages the periphery of the ribbon on the unfilled spool and the incremental rotation of the drive wheel is transmitted to the spool by friction therebetween. When the ribbon becomes substantially full the same drive wheel is utilized to sense this occurrence and is then shifted and urged against the periphery of the ribbon on the other spool to cause it to be incrementally rotated and effect winding thereon :and unwinding from the other full spool. This is achieved by mounting the drive wheel on a linkage which simultaneously urges the drive wheel against the periphery of the ribbon and also senses when the spool against which the drive wheel is being urged is substantially full to cause shifting of the drive wheel to engage the periphery of the ribbon on the other spool.

Variations and modifications may be made Within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. A reversing ribbon advancing mechanism comprising means for supporting a pair of spools for rotation in spaced apart relation with a ribbon being interconnected between the two spools to be windable and unwindable on each spool, each of said spools having an axial core about which the ribbon is wound, each of said spools being mounted on their cores for free rotational movement about the axis of the cores, a driving wheel mounted for rotational movement, means upon actuation for incrementally rotating t-he driving wheel, means for supporting the driving wheel for pivotal movement between the cores of the two spools, means for causing the periphery of the wheel to be urged against the periphery of the ribbon wound on one spool to effect winding of the ribbon on said spool upon rotation of said wheel, and means for pivoting the wheel from being urged against the one spool to being urged against the other spool to engage the periphery of the ribbon wound on the other spool to effect winding of the ribbon on the other spool when the one spool has become substantially full of ribbon.

2. A reversing ribbon advancing mechanism comprising means for supporting a pair of spools for rotation in spaced apart relation with a ribbon being interconnected between the two spools to be windable and unwindable on each spool, each of said spools having an axial core about which the ribbon is wound, a driving wheel mounted for rotational movement, means upon actuation for incrementally rotating the driving wheel, the cores of the spools and the axis of rotation of the driving wheel being substantially parallel and the cores and Wheel lying substantially in a common plane, means for supporting the driving wheel for pivotal movement between the cores of the two spools, means for causing the periphery of the wheel to be urged against the periphery of the ribbon Wound on one spool to cause winding of the ribbon on said spool upon rotation of said wheel, and means for pivoting the wheel from being urged against the one spool to being urged against the other spool to engage the periphery of the ribbon wound on the other spool to effect winding of the ribbon on the other spool when the one spool has become substantially full of ribbon.

3. A reversing ribbon advancing mechanism comprising means for supporting a pair of spools for rotation in spaced apart relation with a ribbon being interconnected between the two spools to be windable and unwindable on each spool, each of said spools having an axial core about which the ribbon is wound, a driving wheel mounted for rotational movement, means upon actuation for incrementally rotating the driving Wheel, means for supporting the driving wheel for pivotal movement between the cores of the two spools, means for causing the periphery of the wheel to be urged against the periphery of the ribbon wound on one spool to provide frictional engagement therebetween to effect winding of the ribbon on said spool, the periphery of said ribbon forcing pivoting of the driving wheel support means against the urging means, and means upon a predetermined pivotal movement of the driving wheel support means for pivoting the wheel from being urged against the one spool to being urged against the other spool to engage the periphery of the ribbon wound on the other spool to effect winding of the ribbon on the other spool.

4. The invention as defined in claim 3 in which the means for incrementally rotating the wheel includes a ratchet wheel connected to the driving wheel and a pawl engageable with the ratchet wheel to incrementally rotate the ratchet wheel and driving wheel in one direction irrespective of against which spool the driving Wheel is urged.

5. The invention as defined in claim 4 in which there is provided one way clutch means engageable with the ratchet wheel to prevent reverse rotation of the ratchet wheel and driving wheel.

6. A reversing ribbon advancing mechanism comprising means for supporting a pair of spools for rotation in spaced apart relation with a ribbon being interconnected between lthe two spools to be windable and unwindable on each spool, each of said spools having an axial core about which the ribbon is wound, a driving wheel mounted for rotational movement, means upon actuation for incrementally rotating the driving wheel, means for supporting the d-riving wheel for pivotal movement between the cores of the two spools, said means including a lever pivoted intermediate its length and having two arm portions with the wheel being carried by one arm portion, spring urged means engaging the other arm portion for effecting pivotal urging of the lever to cause the periphery of the wheel to be urged against the periphery of the ribbon wound on on'e spool to cause winding of the ribbon on said spool upon rotation of said wheel, and means responsive to the amount of ribbon on the one spool for pivoting the wheel from being urged against the one spool to being urged against the other spool to engage the periphery of the ribbon wound on the other spool to effect winding of the ribbon on the other spool when the one spool has become substantially full of ribbon.

7. The invention as defined in claim 6 in which the other arm portion includes a cam surface; and the spring urged means includes a link having a cam surface that is engageable with the cam surface of the arm, said cam surfaces being slidably engaged and a spring connected to the link to pivot it in one direction to urge the arm portion to pivot to force the wheel against the periphery of the ribbon on a spool.

8. The invention as defined in claim 7 in which the arm portion includes a pair of cam surfaces intersecting to form an apex; the link includes a pair of cam surfaces intersecting to form an apex; said wheel being urged against the one spool when the apex of the arm portion is on one side of the apex of the link with a cam surface of each engaging and urging the wheel against the other spool when the apex of the arm portion is on the other side of the apex of the link with the other cam surfaces of each.

9. The invention as defined in claim 6 in which the spring means includes a pivoted link having a portion formed to provide a pair of cam surfaces intersecting at an apex and means fo'r pivoting the link in one direction; the arm portion includes a follower engageable with one 7 8 Surface to urge the lever to pivot in one direction and 631,413 8/ 1899 Spiro 197-160 engageable with the other surface to urge the lever to be 1,928,685 10/ 1933 Dugdale 1011-336 pivoted in the other direction. 3,090,296 5/ 1963 Pechmann 101-336 X References Cited 5 ROBERT E. PULFREY, Primary Examiner. UNITED STATES PATENTS E. T. WRIGHT, Assistant Examiner.

432,295 7/1890 Blickensderfer 197-161 

1. A REVERSING RIBBON ADVANCING MECHANISM COMPRISING MEANS FOR SUPPORTING A PAIR OF SPOOLS FOR ROTATION IN SPACED APART RELATION WITH A RIBBON BEING INTERCONNECTED BETWEEN THE TWO SPOOLS TO BE WINDABLE AND UNWINDABLE ON EACH SPOOL, EACH OF SAID SPOOLS HAVING AN AXIAL CORE ABOUT WHICH THE RIBBON IS WOUND, EACH OF SAID SPOOLS BEING MOUNTED ON THEIR CORES FOR FREE ROTATIONAL MOVEMENT ABOUT THE AXIS OF THE CORES, A DRIVING WHEEL MOUNTED FOR ROTATIONAL MOVEMENT, MEANS UPON ACTUATION FOR INCREMENTALLY ROTATING THE DRIVING WHEEL, MEANS FOR SUPPORTING THE DRIVING WHEEL FOR PIVOTAL MOVEMENT BETWEEN THE CORES OF THE TWO SPOOLS, MEANS FOR CAUSING THE PERIPHERY OF THE WHEEL TO BE URGED AGAINST THE PERIPHERY OF THE RIBBON WOUND ON ONE SPOOL TO EFFECT WINDING OF THE RIBBON ON SAID SPOOL UPON ROTATION OF SAID WHEEL, AND MEANS FOR PIVOTING THE WHEEL FROM BEING URGED AGAINST THE ONE SPOOL TO BEING URGED AGAINST THE OTHER SPOOL TO ENGAGE THE PERIPHERY OF THE RIBBON WOUND ON THE OTHER SPOOL TO EFFECT WINDING OF THE RIBBON ON THE OTHER SPOOL WHEN THE ONE SPOOL HAS BECOME SUBSTANTIALLY FULL OF RIBBON. 